Berry polyphenols may benefit learning and memory, for mice at least

Polyphenols from berries may offer significant benefits for learning and memory associated with age-related cognitive decline, according to two new papers from France.

Data published in Frontiers in Behavioral Neuroscience​​ indicated that eight weeks of polyphenol supplementation were associated with improvements in spatial strategy for middle-aged mice in a water maze, a test of spatial learning and memory.

“The present results show that learning alterations in the early stage of aging can be overcome with a nutritional intervention with polyphenols,”​ wrote the authors, led by Julien Bensalem from the University of Bordeaux.

“Our study focused on spatial learning in mice but other potential effects of dietary polyphenols on other kinds of memory must be studied more thoroughly. Thus, polyphenols are potential food nutrients that can help in the prevention of the age-related cognitive decline and our results suggest that they can play an important role for memory early in life.”​

Scientists from French company Activ’Inside also collaborated on the studies, and they provided the grape extracts used in the polyphenol-rich extract from grape (Vitis vinifera​ L.) and blueberry (Vaccinium angustifolium​). The blueberry extract was provided by NutraCanada.

Study details​

The researchers divided adult and middle-aged mice into two groups: one received a control diet and the other had the diet supplemented with the polyphenol-rich berry extract for eight weeks.

Results showed that the middle-aged animals fed the control diet did indeed display spatial learning deficits, which was evidence of age-related cognitive decline. Feeding this age group the berry extract, however, was found to counter these age-induced effects.

The researchers found that the brain biology of the berry-fed animals was different from their controls, with this group not displaying any reduction in the expression of hippocampal calmodulin kinase II (CaMKII) mRNA levels. CaMKII is implicated in neuronal health, synaptic plasticity and long-term memory, said the researchers.

“Thus these data suggest that supplementation with polyphenols could be an efficient nutritional way to prevent age-induced cognitive decline,” ​they wrote.

The same authors also wrote a review, published in Nutrition and Aging​​. ​In the review, Dr Bensalem and his co-authors note that berry polyphenols may exert beneficial effects on several types of memory and brain plasticity via their antioxidant activity and/or their effect on neuronal signal transduction and inflammation.

“Collectively, the data accumulated so far suggest that dietary polyphenols can modulate brain health and function, and strengthen the importance of fruit consumption for a healthy brain aging and the prevention of age-related diseases,” ​they wrote. “However, further preclinical work is needed to determine the most neuroactive nutraceutical formulations, whether through the diet or supplement, to subsequently design and perform informative clinical trials.”​